DLC and PVD coating durability

K

knife chop

Joined
Feb 11, 2014
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816
Hello,

I wanted to know how durable these coatings are. they are offered by a few manufacturers. I've googled to see how much they wear when you baton with no luck. can anyone post pictures or link a thread where its been discussed before? Thanks
 
They stand up very well, but PVD isn't a coating, it stands for Physical Vapor Deposition, it is however used to apply coatings, i.e. DLC, among others.
 
9blades said:
They stand up very well, but PVD isn't a coating, it stands for Physical Vapor Deposition, it is however used to apply coatings, i.e. DLC, among others.
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Well by that logic DLC can be a number of different materials
 
Sir, I'm 14 years old, honestly my understanding of that Wikipedia page is shaky at best, I'd appreciate it if you spelled it out for me. So I won't guarantee I'll have a reply for your next comment, I'm out of my depth here. :)
 
knife chop said:
No wonder busse knives aren't DLC coated...
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:confused:

The coating on any knife will wear over time, given it's used on enough abrasive material. It all depends on what you are cutting, dense/dry/seasoned hardwood will eat the coating faster than green/moist/non-hardwood. Another variable is the quality of the coating and the way in which it is applied.
 
RevDevil said:
:confused:

The coating on any knife will wear over time, given it's used on enough abrasive material. It all depends on what you are cutting, dense/dry/seasoned hardwood will eat the coating faster than green/moist/non-hardwood. Another variable is the quality of the coating and the way in which it is applied.
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You are right regarding the quality of the coating. I have folder and a fixed blade with cerakote and both coatings wore easily. But recently I bought a freeman outdoor knife and it's cerakote just would not scrape off like my previous knives.
 
DLC is short for TDLC which is Tungsten diamond like Carbon which is Physically Deposited Vaporized Tungsten Carbide which has an HRC (hardness Rockwell C Scale) of 72. Most knife blades are hardened to 60 + or - HRC. So a TDLC coat is much harder than the substrate, but it is quite thin. The lack of coating thickness can cause a lack of corrosion resistance. It can also cause a lack of scratch resistance because a coarse abrasive can get to the substrate through the coating.
Anodized Aluminum is coated with Al2O3 (Aluminum Oxide) which is an abrasive used in sharpening stones (India), but the thickness is only 0.0003" sitting on a soft substrate. Al2O3 is even harder than TDLC, but neither reaches their full potential when applied in such thin coatings.
 
9blades said:
Sir, I'm 14 years old, honestly my understanding of that Wikipedia page is shaky at best, I'd appreciate it if you spelled it out for me. So I won't guarantee I'll have a reply for your next comment, I'm out of my depth here. :)
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I think he means this;

Diamond-like carbon (DLC) exists in seven different forms[1] of amorphous carbon materials that display some of the typical properties of diamond.
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soooooo
it doesn't protect from rust.
ONLY protects from scratchings if it's thick enough, if not, then not,
and adds something like a plus on the external hardness of the knife, taking it from 58/60 to 72 HR.

I was wrongly convinced that it was like a pvd dlc was like a super ultra coating very durable, much superior to teflon, epoxi, and whatever, wich added rust resistance, scratiching resistance, and making the blade generally more durable.
 
marthinus said:
According to this article there is an improvement in corrosion resistance in the use of DLC in desalination plant when applied to 316 stainless:

https://www.sciencedirect.com/science/article/pii/S0011916416317167
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That is a strange claim to make, given what we learned about DLC promoting rust on actual stainless (while leaving uncoated steel areas pristine no less!) on this other thread...:

https://www.bladeforums.com/threads/what-the-rusty-blade-coatings-explain-please.1112532/page-2

This lead to the hilarious defense that these particular coatings were never meant to protect from rust, but were only to cut reflective glare. I kid you not.

In that thread you could also read these hilarious posts:


jimmyd1982 said:
So you're saying rust is what? A frame of mind? It will only develop if you worry about it?

I sure wish I knew that when I lived on the Florida coast, it would have solved a lot of problems for me.
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the kid said:
So you carry some cloth with you at all times and use it every time you use your knife.
Out of curiosity; why not get a stainless knife instead?
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Yes, the obvious is hard to grasp sometimes...

The DLC issue in the other thread is precisely why I tended to stick with older fashioned Cerakoating, despite its finite endurance, rather than go for some of the newer "harder than hard" vapor coating: I never trusted the notion that a "real" coating could be physically thin, no matter how hard wearing it may be.

On the other hand, the problem with Cerakoating, and other "powder-type" paint coatings, is that too much emphasis is put on surface preparation (sandblasting) and paint adhesion, and not enough on the paint's own surface hardness. The Chris Reeves one piece knives are somewhat like that. The reality is that a lot of cheap paint coated Chinese knives have a harder paint surface, while being carelessly applied to non-sandblasted surfaces: They do occasionally flake as a result, but I have found the harder paint surface, in the end, wears down noticeably slower from typical non-batoning knife uses...

Stainless doesn't really need any coating, especially if a tight sheath is going to put rub marks in the paint, but it is always nice to know you are overkilling an issue... Better than defending the notion of a finish that is a "vapor" or even that causes rust on stainless(!), in any case...

Gaston
 
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